Glossary - T

T.120

The International Telecommunication Union - Telecommunication [Standardization Sector] (ITU-T) standard for multipoint data conferencing. T.120 provides the protocols for establishing and managing data flow, connections, and conferences. Support for T.120 enables data transfer from conferencing applications, such as file transfer and application sharing, to operate in conjunction with H.323 connections.

tag

For Indexing Service, one or more terms that identify an element in a query, such as weight, phrase, property, or regular expression. For example, the tag {prop name=created} specifies the Created property in a query.

See also:
propertyquery

TAPI

TAPI server security file

A file that stores information about the telephony devices for each installed telephony service provider, including the addresses that are assigned to each device and the users who are authorized to use each device.

target

A Universal Naming Convention (UNC) path that corresponds to a namespace root or folder.

See also:
DFS linkDFS rootDistributed File System (DFS)

target journaling

For Message Queuing, the process of storing copies of incoming messages. Target journaling is configured on a queue basis. When target journaling is enabled, a copy of each incoming message is placed in the target journal when the message is retrieved (read) from the destination queue.

See also:
journalMessage Queuingsource journaling

target priority

A setting that specifies whether a specific target in a referral should be listed first or last, or first or last among targets of equal cost.

Task Manager

A tool that provides information about programs and processes running on the computer. Using Task Manager, you can end or run programs, end processes, and display a dynamic overview of your computer`s performance.

See also:
processprogram

taskbar

The bar that contains the Start button and appears by default at the bottom of the desktop. You can click the taskbar buttons to switch between programs. You can also hide the taskbar, move it to the sides or top of the desktop, and customize it in other ways.

See also:
desktopnotification area

taskpad

A details pane view that displays shortcuts to commands that are available for the selected snap-in in the console tree. Users can run a command by clicking a task.

See also:
console treedetails panesnap-in

TCP/IP

TDI

teaming network adapters

A configuration method that provides fault tolerance by grouping network adapters on multiple ports to a single physical network segment. For example, if connections through one port fail (due to failure of the adapter, cable, switch port, or switch), another port is activated automatically. Teaming network adapters work transparently to the operating system and other devices on the network.

See also:
devicefault tolerancenetwork adapterport

Telephony API (TAPI)

An application programming interface (API) used by communications programs to work with telephony and network services.

telephony switch

A computer or electromechanical device that controls the routing and operation of a signal path.

Telnet

A protocol that enables an Internet user to log on to and enter commands on a remote computer linked to the Internet, as if the user were using a text-based terminal directly attached to that computer. Telnet is part of the TCP/IP suite of protocols. The term telnet also refers to the software (client or server component) that implements this protocol.

temporary address

An Internet Protocol version 6 (IPv6) address that uses an interface identifier that changes over time and that is not derived from a hardware property, such as a media access control (MAC) address. A temporary address makes it difficult to track the identity of a computer on the Internet across sessions.

TGS

TGT

Thread Count

thumbnail

A miniature version of an image that is often used for quick browsing through multiple images.

ticket

A set of identification data for a security principal, issued by a domain controller for purposes of user authentication. Two forms of tickets in Windows are ticket-granting tickets (TGTs) and service tickets.

ticket-granting ticket (TGT)

A credential issued to a user by the Kerberos Key Distribution Center (KDC) when the user logs on. The user must present the TGT to the KDC when requesting session tickets for services. Because a TGT is normally valid for the life of the user`s logon session, it is sometimes called a user ticket.

time server

A computer that periodically synchronizes the time on all computers within a network. This ensures that the time used by network services and local functions remains accurate.

See also:
server

time slice

A brief period of time during which a particular task is given control of the microprocessor in a time-sharing multitasking environment. A computer`s processor is allocated to an application, usually measured in milliseconds. Also called quantum.

time stamp

A certification specifying that a particular message existed at a specific time and date. In a digital context, trusted third parties generate a trusted time stamp for a particular message by having a time stamping service append a time value to a message and then digitally signing the result.

See also:
service

Time to Live (TTL)

For Internet Protocol (IP), a field in the IP header of an IP packet that indicates the maximum number of links over which the packet can travel before being discarded by a router.
For DNS, TTL values are used in resource records within a zone to determine how long requesting clients should cache and use this information when it appears in a query response answered by a DNS server for the zone.

time-out error

A condition where an expected character is not received in time. When this condition occurs, the software assumes that the data has been lost and requests that it be resent.

title bar

The horizontal bar at the top of a window that contains the name of the window. On many windows, the title bar also contains the program icon, the Maximize, Minimize, and Close buttons, and the optional ? button for context-sensitive Help. To display a menu with commands such as Restore and Move, right-click the title bar.

See also:
maximizeminimize

TLS

token

Any nonreducible textual element in data that is being parsed. For example, the use in a program of a variable name, a reserved word, or an operator. Storing tokens as short codes shortens program files and speeds execution.
For networking, a unique structured data object or message that circulates continuously among the nodes of a token ring and describes the current state of the network. Before any node can send a message on the network, it must first wait to control the token.

Token Ring

The Institute of Electrical and Electronics Engineers (IEEE)&nbsp;802.5 standard that uses a token-passing technique for media access control (MAC). Token Ring supports media of both shielded and unshielded twisted pair wiring for data rates of 4 megabits per second (Mbps) and 16 megabits per second.

tombstone lifetime

top-level domains

Domain names that are rooted hierarchically at the first tier of the domain namespace directly beneath the root (.) of the DNS namespace. On the Internet, top-level domain names such as .com and .org are used to classify and assign second-level domain names (such as microsoft.com) to individual organizations and businesses according to their organizational purpose.

See also:
domaindomain nameDomain Name System (DNS)domain namespacerootsecond-level domain

topological database

An overview of networks and how they relate to routers. Routers in the same area have the same topological database.

See also:
router

topology

The physical layout of computers, cables, switches, routers, and other components of a network. Topology also refers to the underlying network architecture, such as Ethernet or Token Ring. In Active Directory replication, the set of connections that domain controllers use to replicate information among themselves.

See also:
Active Directory replicationdomain controller

touch-tone dialing

A form of dialing that uses multiple-tone signaling. The user hears a series of tones (beeps) when dialing. Push-button telephones usually use touch-tone dialing.

See also:
pulse dialing

trace log

A type of log generated when the user selects a trace data provider using the Performance tool. Trace logs differ from counter-data logs in that they measure data continuously rather than taking periodic samples.

transaction

For Message Queuing, the pairing of two or more actions that are performed together as a single action; the action succeeds or fails as a whole. Using Microsoft Distributed Transaction Coordinator (MS DTC) ensures that either both actions succeed or neither is executed.

transactional dead-letter queue

For Message Queuing, a queue that stores transactional messages that cannot reach their destination queue. Transactional dead-letter queues store failed messages on the computer on which the message expired. Messages in these queues are written to disk and are therefore recoverable.

transactional message

For Message Queuing, a message that can be sent and received only from within a transaction. This type of message returns to its prior state when a transaction is terminated abruptly. A transactional message is removed from a queue only when the transaction is committed; otherwise, it remains in the queue and can be subsequently read during another transaction.

transitive trust

A trust relationship that flows throughout a set of domains, such as a domain tree, and forms a relationship between a domain and all domains that trust that domain. For example, if domain A has a transitive trust with domain B, and domain B trusts domain C, then domain A trusts domain C. Transitive trusts can be one-way or two-way, and they are required for Kerberos-based authentication and Active Directory replication.

Transmission Control Protocol/Internet Protocol (TCP/IP)

A set of networking protocols widely used on the Internet that provides communications across interconnected networks of computers with diverse hardware architectures and various operating systems. TCP/IP includes standards for how computers communicate and conventions for connecting networks and routing traffic.

See also:
Internet Protocol (IP)protocol

transmitting station ID (TSID) string

A string that specifies the transmitter subscriber ID sent by the fax machine when sending a fax to a receiving machine. This string is usually a combination of the fax or telephone number and the name of the business. It is often the same as the called subscriber ID.

See also:
called subscriber ID (CSID) stringstring

Transport Driver Interface (TDI)

A common set of routines for network layer components that communicate with the session layer of the Open Systems Interconnection (OSI) model. These routines allow software components above and below the transport layer to be mixed and matched without reprogramming.

See also:
Open Systems Interconnection (OSI) reference model

Transport Layer Security (TLS)

A protocol that provides communications privacy and security between two applications communicating over a network. TLS encrypts communications and enables clients to authenticate servers and, optionally, servers to authenticate clients. TLS is a more secure version of the Secure Sockets Layer (SSL) protocol.

See also:
authenticationprotocolSecure Sockets Layer (SSL)

transport provider

The driver and support files that provide transport services in a networking environment.

trap

In Simple Network Management Protocol (SNMP), a message sent by an agent to a management system indicating that an event has occurred on the host running the agent.

See also:
agenteventhostSimple Network Management Protocol (SNMP)

tree root trust

A trust that is automatically established when you add a new domain tree (the tree root domain) to an Active Directory forest (the forest root domain). Tree root trusts are transitive and two-way.

tree view

A hierarchical representation of the folders, files, disk drives, and other resources connected to a computer or network. For example, Windows Explorer uses a tree view to display the resources that are attached to a computer or a network.

See also:
resource

triggered update

A type of Routing Information Protocol (RIP) announcement that occurs when network topology changes. With triggered updates, the update announcing network topology changes is sent almost immediately rather than waiting for the next periodic announcement. Triggered updates improve the convergence time (the time it takes for a router to update its routing tables) of RIP internetworks, but at the cost of additional broadcast traffic while the triggered updates are propagated.

See also:
routingRouting Information Protocol (RIP)

Triple DES (3DES)

An implementation of Data Encryption Standard (DES) encryption that employs three iterations of cryptographic operations on each segment of data. Each iteration uses a 56-bit key for encryption, which yields 168-bit encryption for the data. Although 3DES is slower than DES because of the additional cryptographic calculations, its protection is far stronger than DES.

See also:
cryptographyData Encryption Standard (DES)encryption

Trivial File Transfer Protocol (TFTP)

A protocol used to download the initial files needed to begin the installation process.

See also:
protocol

Trojan horse

A program that appears to be useful or harmless but that contains hidden code designed to exploit or damage the system on which it is run. Trojan horse programs are most commonly delivered to users through e-mail messages that misrepresent the program's purpose and function. Also called Trojan code.

See also:
virus

TrueType font

A type of computer font that can be scaled to any size. TrueType fonts are clear and readable in all sizes and can be sent to any printer or other output device that is supported by Windows.

See also:
font

trust path

A series of trust relationships that authentication requests must follow between domains. Domain controllers determine the trust path for all authentication requests between a domain controller in the trusting domain and a domain controller in the trusted domain.

trust relationship

A logical relationship established between domains to allow pass-through authentication, in which a trusting domain honors the logon authentications of a trusted domain. User accounts and global groups defined in a trusted domain can be given rights and permissions in a trusting domain, even though the user accounts or groups don`t exist in the trusting domain`s directory.

See also:
authenticationdomainglobal groupgrouppermissionuser account

trusted domain object (TDO)

An object that represents one direction of a trust relationship. When trust relationships are established, unique TDOs are created and stored in the domain. For example, when a two-way trust is established, two TDOs are created.

TTL

TTY

A communications device that consists of a keyboard and a printer. Each keystroke on the sending machine generates a character code that is sent to the receiving machine, which prints the character. TTY is usually associated with a video display that is treated like a teletypewriter or that emulates one.

tunnel

A logical connection over which data is encapsulated. Typically, both encapsulation and encryption are performed, and the tunnel is a private, secure link between a remote user or host and a private network.

tunnel server

tunneling protocol

A communication standard used to manage tunnels and encapsulate private data. Data that is tunneled must also be encrypted to be a virtual private network (VPN) connection. Two commonly used tunneling protocols are the Point-to-Point Tunneling Protocol (PPTP) and Layer Two Tunneling Protocol (L2TP).